Experimental and theoretical insight into spectroscopic properties and bioactivity of 4-(4-formylbenzylidene)-2-phenyloxazol-5(4H)-one dye for future applications in biochemistry

Abstract The synthesized 4-(4-formylbenzylidene)-2-phenyloxazol-5(4H)-one was characterized by NMR and IR spectroscopy. The steady-state and time resolved measurements were applied to investigate its solvatochromism, determine dipole moments and elucidate its biological activity. Photophysical properties of the dye were studied in solvents of different polarities. Solute-solvent interactions were analyzed by means of multi-linear regression method using Catalan parameters whereas linear solvent correlation techniques like Lippert-Mataga, McRae and Bakhshiev polarity functions were used to evaluate the singlet excited state dipole moment. The achieved results indicate that the electronic absorption and fluorescence spectra of the oxazolone dye exhibit positive solvatochromism. Moreover, solvent polarizability is the major factor responsible for the observed red shift, thus the non-specific interactions mainly control the photophysical properties of the dye while the contribution of the specific interactions is weaker and mainly depend on solvent acidity. The rise in dipole moment of the dye occurs upon excitation due to the π-electron density redistribution. The spectroscopic measurements were supported by computational calculations including geometry optimization, spectral and physicochemical properties. The studies were also extended to evaluate bioactivity of the dye. The interaction between oxazolone dye and Concanavalin A was investigated by the fluorescence anisotropy method. The ion transporter action, especially sodium‑potassium pump function, and water transport in epithelial tissue were elucidated by the estimation of skin resistance.